Abstract: We examine the link between new employees in leading positions and subsequent productivity in small- and medium-sized enterprises (SMEs). Managers and professionals are likely to possess important tacit knowledge. They are also in a position to influence the employing firm. Exploiting rich and comprehensive panel data for Sweden in the 2001-2010 period and employing semi-parametric and quasi-experimental estimation techniques, we find that newly recruited professionals have a positive and statistically significant impact on the productivity of the hiring SME. For newly recruited managers there is no general link to the productivity of the hiring SME. We also find that professionals with experience from international firms and enterprise groups contribute the most to total factor productivity. Overall, the findings suggest the importance of mobility of key personnel for productivity-enhancing knowledge spillovers to SMEs.